Mr. Barry was fiercely dedicated to protecting the secret formula of WD-40, not to mention its trademarks and distinctive container. The company never patented WD-40, in order to avoid having to disclose the ingredients publicly. Its name became synonymous with the product, like Kleenex.

Mr. Barry acknowledged in interviews with Forbes magazine in 1980 and 1988 that other companies, including giants like 3M and DuPont, made products that closely resembled WD-40.

“What they don’t have,” he said, “is the name.”

Mr. Barry brought marketing coherence and discipline to the company. He spruced up the packaging and increased the advertising budget, but most of all he pushed for distribution. He emphasized free samples, including the 10,000 the company sent every month to soldiers in the Vietnam War to keep their weapons dry.

Within a little more than a decade, Mr. Barry was selling to 14,000 wholesalers, up from 1,200 when he started.

He kept tight control of the product. When Sears wanted to package WD-40 under its own label, Mr. Barry said no. When another big chain wanted the sort of price concessions to which it was accustomed, he refused.

He pushed to get WD-40 into supermarkets, where people buy on impulse. He also began an aggressive effort to sell WD-40 in foreign countries.

“We may appear to be a manufacturing company,” Mr. Barry said to Forbes, “but in fact we are a marketing company.”